Effect of in-office bleaching agent on the surface roughness and microhardness of nanofilled and nanohybrid composite resins.

Background: To compare the surface roughness and microhardness of Ceram.x® SphereTEC™ one and Filtek Z350 XT after in-office bleaching with Pola office. Methods: Twenty samples each of (10 mm diameter and 2 mm height) Ceram.x® SphereTEC™ one and Filtek Z350 XT were prepared. The samples were subjected to three bleaching sessions with 35% hydrogen peroxide (Pola office) with a seven-day interval between each session. Surface roughness and microhardness of the prepared samples prior to and after the bleaching regimen were measured using a profilometer and Vickers hardness tester, respectively. Results: A significant reduction (p <0.001) in the surface hardness of Filtek Z350 XT from 27.67 ± 2.10 to 17.83 ± 1.36 Vickers hardness number (VHN) was observed after the bleaching whereas no significant reduction in surface hardness was observed with Ceram.x® SphereTEC™ one. The adjusted mean (estimated marginal mean) microhardness after bleaching for Ceram.x ® SphereTEC™ one (35.79 ± 1.45) was significantly higher than Filtek Z350 XT (19.54 ± 1.45) (p < 0.001). However, in-office bleaching of these materials did not significantly alter their surface roughness. Conclusions: In office-bleaching with 35% hydrogen peroxide can reduce the microhardness of nanofilled composite. However, the surface roughness was not influenced by the bleaching procedure in both nanohybrid and nanofilled composite resin materials.

Comparative Evaluation of Corneal Storage Medias Used as Tooth Avulsion Medias in Maintaining the Viability of Periodontal Ligament Cells Using the Cell Counting Kit-8 Assay.

Purpose: The prime factor in determining the success of reimplantation of an avulsed tooth is the maintenance of the viability of periodontal ligament fibroblast cells (PDFC). This study aims to evaluate and compare Mc Carey Kaufman media (MK), Cornisol, Dulbecco's Modified Eagles Medium (DMEM), Hanks Balanced Salt Solution (HBSS) and distilled water in preserving the viability of the PDFC using the Cell Counting Kit-8 assay (CCK-8). Methods: Cryopreserved PDFC were suspended in DMEM and incubated in CO2 incubator at 370C with 95% humidity and 5% CO2 for attachment. Once cells attained 80% confluence, they were trypsinised and passed into T-25 culture flasks to expand the culture population. Cells from passage 5 were pooled for experimentation. Trypan blue exclusion test was performed before each experiment to measure cell viability and batches showing more than 95% viability were used in the experiment. The viable PDFC with 1×105 were seeded in 96 well plates and incubated in CO2 incubator at 370C, 95% humidity and 5% CO2 for 24 hours to allow cell attachment. A 100µL of the experimental media were added in the wells and the cells were exposed for 1, 24 and 48 hours respectively. The viability was determined using the CCK-8. Experiment was performed in triplicates and data was subjected to statistical analysis. Results: Statistical analysis was performed using repeated measure ANOVA, ANOVA, and post-hoc Bonferroni test with the significance level p<0.05. The values are as follows: MK (1.3146 ±0.0588, 1.9012±0.0511, 2.0723±0.1211) > Cornisol (1.2399±0.0548, 1.9596±0.0652, 1.9592±0.1361) >DMEM (1.1914±0.0691, 1.8479±0.0116, 2.0718±0.0795) > HBSS (0.3665±0.0814, 0.0184±0.0010, 0.0248±0.0042) >distilled water (0.0122±0.0033, 0.0225±0.0085, 0.0104±0.0008) at 1 hour, 24 hours and 48 hours respectively. MK >Cornisol>DMEM>HBSS>distilled water. Conclusion: It can be concluded that the corneal preservation solutions showed promising results in preserving periodontal ligament cell viability for extended time periods.

Assessment of knowledge, attitude and practices among dental practitioners on methods of infection control while carrying out dental procedures during novel coronavirus (COVID-19) pandemic.

INTRODUCTION: dental procedures produce bio-aerosols that can carry the highly contagious COVID-19 virus. Hence, the entire dental care team has to follow the current COVID-19 related infection control protocols. The study aims to assess the knowledge, attitude, and practices associated with infection control methods during dental procedures among dental practitioners during the COVID-19 pandemic in India. METHODS: the online questionnaire consisted of four sections namely, demographic details, eight questions on knowledge, four questions on attitude and eight questions on the practice of dentists during COVID-19 pandemic. One point was attributed for a correct response and zero point for an incorrect response. The study used descriptive statistics and binary logistic regression models in Jamovi 1.8.1 to establish relationships between knowledge, attitude, and practices among dental professionals and their demographic characteristics. RESULTS: among 384 dentists, 294 (76.6%) were aware of the hand hygiene methods, 372 dentists (96.9%) were aware of the Personal Protective Equipment (PPE), 343 dentists (89.3%) recorded the body temperature of the patients. One hundred and thirty eight (138) dentists (35.9%) did not use rubber dam and 158 dentists (41.1%) were not aware of the four-handed dentistry. Among the study participants, 57.8% displayed adequate knowledge, 63.8% possessed good attitude and 93.5% followed good practices on COVID-19 appropriate infection control measures during dental procedures. The mean knowledge, attitude, and practice scores were found to be 6.61, 2.04, and 3.38 respectively. Based on multivariable binary logistic regression analysis, it is observed that males (aOR: 0.55, 95% CI 0.35-0.87; p=0.011) have a lower likelihood of having a good knowledge when compared with females after adjusting for the other independent variables in the model. Also, individuals with higher qualifications (aOR: 0.57, 95% CI 0.36-0.92; p=0.022) appear to have lower likelihood of having good knowledge on COVID-19 infection control methods during dental procedure. CONCLUSION: the study concludes that participants possess sound knowledge, attitude and practice on hand hygiene, PPE, patient triage and waiting area modifications at the workplace. However, poor response was noted on the use of rubber dam, remote telephonic screening and four-handed dentistry practice.

Comparison Between Biofilm Production, Phospholipase and Haemolytic Activity of Different Species of Candida Isolated from Dental Caries Lesions in Children.

INTRODUCTION: C.albicans is the most commonly isolated fungal pathogen in the oral cavity, but isolation of non-albicans Candida is increasing in recent years. We wish to demonstrate the virulence factors of Candida spp. isolated from the dental caries lesion of the children as presence of virulence factors determines the pathogenic potential of any microorganism. AIM: To compare biofilm production, phospholipase and haemolytic activity of C.albicans with that of non-albicans species of Candida isolated from dental caries lesions of children to evaluate the role of non- albicans species of Candida in formation of dental caries. MATERIALS AND METHODS: Oral swabs were collected from caries lesion of 100 school children of age 5-10 years with dental caries. Candida isolates were tested for biofilm production, phospholipase and haemolytic activity. Statistical analysis was done by Chi-Square test and Mann-Whitney U test wherever applicable using SPSS version 11.5. RESULTS: Out of the 100 children with dental caries 37 were positive for Candida by smear or culture and 31 by culture. C.albicans was the most prevalent isolate followed by C.krusei, C.tropicalis and C.albicans. Out of 21 C.albicans isolates, 10 (47.6%) showed phospholipase activity and 18 (85.71%) produced biofilm. Of the 10 non-albicans strains, 5 (50%) showed phospholipase activity and 6 (60%) produced biofilm. All isolates of Candida produced haemolysin (100%). CONCLUSION: There was no statistically relevant difference between the virulence factor production by C.albicans and non-albicans species of Candida. In other words, our study shows that both C.albicans and non-albicans species of Candida isolated from caries lesions of the children, produce these virulence factors. So we can say that non-albicans species of Candida also are involved in caries formation.